Chemical effects in transgenic mice bearing oncogenes expressed in mammary tissue.

Three transgenic mouse lines carrying v-Ha-ras (TG-SH), c-myc (TG-M) or c-neu (TG-NK) oncogenes under regulatory control of mouse mammary tumor virus (MMTV) long terminal repeat (LTR) sequences were evaluated for responses to two chemical carcinogens. p-Cresidine, a mutagenic urinary bladder carcinogen, increased the incidence of urinary bladder carcinomas in males and females in all three lines, and these tumors occurred at comparable incidences and grade in transgenic and non-transgenic mice. p-Cresidine did not affect the rates of mammary or salivary gland neoplasms in transgenic mice; these tumors did not occur in non-transgenic littermates.

Forestomach neoplasms in Fischer F344/N rats and B6C3F1 mice exposed to diglycidyl resorcinol ether--an epoxy resin.

Repeated dose (14 days), subchronic (13 wk) and chronic (2 yr) studies were carried out in succession to evaluate the toxic and carcinogenic effects of diglycidyl resorcinol ether (DGRE), a liquid spray epoxy resin, in F344/N rats and B6C3F1 mice. DGRE in corn oil was administered by gavage for 14 consecutive days in the repeated dose study and 5 days/wk in the subchronic and chronic studies. The mortality rate was increased in rats and mice in the repeated dose and subchronic studies.

Effect of 4,4'-oxydianiline on the thyroid and pituitary glands of F344 rats: a morphologic study with the use of the immunoperoxidase method.

F344 rats of both sexes were fed one of three concentrations (0.02, 0.04, 0.

Chronic effects of agar, guar gum, gum arabic, locust-bean gum, or tara gum in F344 rats and B6C3F1 mice.

Diets containing 25,000 (2.5%) or 50,000 ppm (5.0%) agar, guar gum, gum arabic, locust-bean gum or tara gum were fed to groups of 50 male and 50 female F344 rats and B6C3F1 mice for 103 wk.

Chordoma of the spinal cord in a F344 rat.

A chordoma arose in the lumbar region of the vertebral column from the last two vertebrae of a 112 week old female control F344 rat. Macroscopically it was a mass measuring 32 by 22 mm reaching the pelvic region and pressing against the colon and urinary bladder. Histologically the tumor cells were arranged into lobules and the cells grew in cords.